A two-year comparison of resin-based composite tunnel and Class II restorations in a randomized controlled trial

Purpose : To evaluate the performance of total tunnel restoration with resin-based composites compared to Class II resin-based composite restorations in a randomized controlled clinical study. Methods: 63 approximal carious lesions were restored in 38 patients by two experienced operators. The carious dentin and approximal demineralized enamel were completely removed for the tunnel restoration leaving the marginal ridge intact. The occlusal opening was enlarged to the center of the tooth to make access easy. Conservative cavity preparation was performed for the Class II restorations. All cavities were restored with Scotchbond Multipurpose Plus and Z250. At baseline, 1- and 2-year recalls, the restorations were evaluated clinically by two examiners using a modified USPHS rating system and radiographically for recurrent caries. Results: Both types of restorations performed well clinically, and there was no significant difference (P > 0.05) by the chi square test in any category. Recurrent caries was not detected. Only one tunnel restoration had to be replaced with a Class II restoration because of falling of the restoration with the marginal ridge after 2 years. However, no significant difference in the survival rates (P > 0.05) could be demonstrated between the restorations by the log-rank test.